This invention is in the field of 5-secondary alkylidene hydantoins.
More particularly, this invention is directed to: (a) the novel 5-secondary alkylidene hydantoins recited in the following Summary; and (b) the novel process for preparing 5-secondary alkylidene hydantoins which is recited in Embodiment A, infra, and the embodiments thereunder.
The Kirk-Othmer Encyclopedia (Second Edition, 1966, Vol. 11, pages 144-145) teaches that:
1. The reaction of hydantoins with aromatic or heterocyclic aldehydes occurs at the C-5 position and gives unsaturated hydantoins. ##STR4## where R is phenyl, substituted phenyl, furyl, pyrryl, pyridyl, quinolyl, or indolyl.
2. The reaction of hydantoins with aliphatic aldehydes has met with variable success.
3. Several cyclic ketones or keto compounds, including cyclohexanone, isatin, and parabanic acid (2,4,5-imidazolidinetrione) have been successfully condensed with hydantoins, to obtain products analogous to (D).
An apparently undated 25 page bulletin entitled "HYDANTOINE" which was circulated by Nobel Hoechst Chimie, Tour Nobel, 92, Puteaux (France) teaches the reaction between heterocyclic aldehydes and hydantoin wherein the two hydrogens on the 5-carbon atom of the hydantoin are replaced with ##STR5## in which R is a heterocyclic moiety.
5-iso-propylidenehydantoin, ##STR6## is known. Its preparation is taught by Tatsuoka et al, J. Pharm. Soc. Japan, 1949, 69, 294-7, Chemical Abstracts 1950, 44, 2513e. They prepared it (5-iso-propylidenehydantoin) by boiling S-benzyl-dl-penicillamine hydantoin with 15% sodium hydroxide and neutralizing with HCl.
U.S. Pat. No. 2,861,079 (Britton et al) teaches a method for forming certain unsaturated hydantoins wherein a hydantoin is reacted with an aldehyde having at least 4 carbon atoms per molecule in the presence of: (a) water, or a lower alcohol, or water and such alcohol; plus (b) a monoalkanolamine having 2-4 carbon atoms per molecule.
Doyle et al, J. Chem. Soc. 1955, 2265-73 (Chemical Abstracts 1956, 50, 8602g at 8603b) teach the preparation of 5-iso-propylidenehydantoin via the reaction of acetone with 2-thiohydantoin in piperdine to yield 5-iso-propylidene-2-thiohydantoin which is then desulfurized with chloroacetic acid to yield 5-iso-propylidenehydantoin.
The 5-secondary alkylidene hydantoins of this invention are useful for preparing alpha-keto carboxylic acids according to the process of our copending application Ser. No. 703,173 filed Oct. 7, 1976, and now abandoned; said application is assigned to W. R. Grace & Co.
Alpha-keto carboxylic acids (which are also referred to herein as "alpha-keto acids" and as "keto acids") have many uses including but not limited to those listed below.
1. Keto acids are useful as starting materials for the synthesis of amino acids (Yakabson et al, Biokhimya, 1949, 14, 14-19, Chemical abstracts, 1949, 43, 5084d, Sakurai, J. Biochem. (Tokyo), 1958, 45, 379-85, Chemical abstracts 1958, 52, 18537h, Japanese Pat. No. 18,711 (1962), Chemical Abstracts, 1963, 59, 11660p, and Japanese Pat. No. 6884 (1963), Chemical Abstracts, 1963, 59, 11662d).
2. Keto acids are useful as pharmaceuticals against uremia for promoting protein synthesis and for suppressing urea formation (Walser, German Offenlegungsschrift No. 2,335,215 (1974)).
3. Keto acids are useful as catalysts in the copolymerization of unsaturated monomers (Dutch patent publication No. 298,715, Chemical Abstracts, 1966, 64, 6842d, and British patent specification No. 1,018,109 (1966)).
4. Keto acids are useful as hair treating agents to protect hair against hydroperoxides (German Auslegeschrift No. 1,158,213 (1963)).